Publication:
Three-Dimensional Effects on Plunging Airfoils at Low Reynolds Numbers

Loading...
Thumbnail Image
Identifiers
Publication date
2020-10-01
Defense date
Advisors
Tutors
Journal Title
Journal ISSN
Volume Title
Publisher
American Institute of Aeronautics and Astronautics
Impact
Google Scholar
Export
Research Projects
Organizational Units
Journal Issue
Abstract
We present two-dimensional and three-dimensional (3-D) direct numerical simulations of large-amplitude plunging maneuvers at Reynolds numbers of Re=1000 and 5000, with velocity ratios of G=0.5, 1, and 2. For all cases, the evolution of the force coefficients is qualitatively similar. The lift coefficient presents a pronounced peak toward the end of the acceleration phase of the maneuver, a local minimum in the deceleration phase, and a second peak at the end of the maneuver. The amplitude of the main peak increases linearly with G, with limited effect of the Reynolds number and a negligible effect of the three-dimensionality of the flow. On the other hand, both the Reynolds number and three-dimensionality have a stronger effect on the amplitude of the maximum value of the lift coefficient at the end of the maneuver, as well as on the subsequent transient decay toward the static values. The comparison of the evolution of the flow structures near the airfoil shows that these differences in the force coefficients are due to subtle interactions between the various vortices generated during the maneuver, as well as to the development of a 3-D boundary layer on the suction side of the airfoil triggered by the instability of the trailing-edge vortices.
Description
Keywords
Freestream velocity, NACA 0012, Lift coefficient, Direct numerical simulation, Trailing edges, Vortices, Boundary layers, Flow visualization, Aspect ratio, Convective boundary condition
Bibliographic citation
AIAA Journal, (2021), 59(1), pp. 64-74.